One Direction worry Zayn Malik will miss their gigs because he is so forgetful

The group are currently in the middle of their 'Take Me Home' world tour and the 'Little Things' singer often causes concern by forgetting to pack - and has even turned up to airports without his passport in the past.

His bandmate Liam Payne said: "Zayn is the most likely to forget his passport, and has done a number of times."

Harry Styles added: "Zayn often forgets to pack his suitcase before tours."

The band's road crew are said to have nicknamed the 20-year-old singer 'Nellie' - in reference to an elephant, an animal famed for its impressive memory - but Zayn has been warned to be more organised ahead of the US leg of the tour, which begins in Florida next month.

A source told The Sun newspaper: "Zayn has been told to get his act together this time."

Meanwhile, One Direction - of which Louis Tomlinson and Niall Horan are also members - have announced plans for a new book.

'Where We Are: Our Band, Our Story' will be released in August and tells the tale of their "phenomenal" story in their own words, as well as featuring "exclusive beautiful photos, backstage snapshots, hand-written annotations and brand new insights into the boys' world".